docs: def add_permission(self):
          """Add permission to Lambda for the API Trigger."""
          statement_id = '{}_api_{}'.format(self.app_name, self.trigger_settings['api_name'])
          principal = 'apigateway.amazonaws.com'
          lambda_alias_arn = get_lambda_alias_arn(self.app_name, self.env, self.region)
          lambda_unqualified_arn = get_lambda_arn(self.app_name, self.env, self.region)
          resource_name = self.trigger_settings.get('resource', '')
          resource_name = resource_name.replace('/', '')
          method_api_source_arn = 'arn:aws:execute-api:{}:{}:{}/{}/{}/{}'.format(
              self.region, self.account_id, self.api_id, self.env, self.trigger_settings['method'], resource_name)
          global_api_source_arn = 'arn:aws:execute-api:{}:{}:{}/*/*/{}'.format(self.region, self.account_id, self.api_id,
                                                                               resource_name)
          add_lambda_permissions(
              function=lambda_alias_arn,
              statement_id=statement_id + self.trigger_settings['method'],
              action='lambda:InvokeFunction',
              principal=principal,
              env=self.env,
              region=self.region,
              source_arn=method_api_source_arn)
          add_lambda_permissions(
              function=lambda_alias_arn,
              statement_id=statement_id,
              action='lambda:InvokeFunction',
              principal=principal,
              env=self.env,
              region=self.region,
              source_arn=global_api_source_arn)
          add_lambda_permissions(
              function=lambda_unqualified_arn,
              statement_id=statement_id + self.trigger_settings['method'],
              action='lambda:InvokeFunction',
              principal=principal,
              env=self.env,
              region=self.region,
              source_arn=method_api_source_arn)
          add_lambda_permissions(
              function=lambda_unqualified_arn,
              statement_id=statement_id,
              action='lambda:InvokeFunction',
              principal=principal,
              env=self.env,
              region=self.region,
              source_arn=global_api_source_arn)